Alternating-current clock



March-24,1931. Y L, HAMMOND 1,797,912

ALTERNATING CURRENTCLOCK l Filed June 18, 1929 5 Sheets-Sheei l Mardi 24, 1931. 1 HAMMOND 1,7975912 ALTERNATINC CURRENT CLOCK Filed Jue 1e, 1929 3 sheets-.sheet 2 do L@ March 24,1931-, .HAMMOND y 1,797,912

' ALTERNATING CURRENT CLOCKv Filed June 18, 1929 5 Sheets-Sheet 3 I 11,1, SI;

vaunted Mar. 24,1931 I finalisation nieu la,

My invention relates Kweneraliy to alternating current clocks oit the synchronous motor driven type id more partleuiarly un- M proveniente the gear train hy which the i motor is connected to the hands oif the clock, and to the method of mounting the motor in the cloclf: it;

llt is one et the ohjects of my invention to provide an improved gear train for'clocks which are driven from the high speed end of the train, having the minimum number ot gears and shaits compatible with compactness and ease oi assembly.

A further object is to provide an improved means for mounting the motor parts upon the clock frame whereby parts ot the motor form reinforcements lor the frame and whereby the magnetic :torces on the armature ot the motor tending to twist the trarne are' minimiaed.

A further oioject is to provide an electric motor driven' clock which is simple in construction, may he readily made in quantity production, may loe easily assembled, and which may he economically.manufactured Other objects will appear from the Jfollowing description, Ireference being had to the accompanying drawings, in which Eig. l is a iront elevation. oi the clock mechanism, portions of the dial and'gears being broken away; l

Fig. 2 is a loottom plan view of the clock mechanism, the dial being shown in section; Fig. 3 is a right side elevation of the mechanism shown in Fig. l;

Fig. 4 is a vertical section 'taken on the line 4-4 ofgFig. 6; n

v i Fig. 5 is a developed view of thedgear train; and

vi Fig. 16 is a section taken on the line 6-6 o'Fig. 3.

The clock of my invention comprises two .frames 10 and 12.' 'Ijhe frames lare joined and held rigidly in suitably spaced relation by four studs 14, each having one end riveted i929. Serial No. 53%,?53..

to the framei andthe other end passing through the trame l@ and secured thereto hy a nut. 1G. y

The motor used to drive the clock comprises a plurality or" suiostantiallyU-shaped lamina- Y tions forming a core i8, several oit the laminations of which project downwardly to form .pole pieces Q0. coil 22 is wound around one of the legs of isi-shaped core 18, and

the frame l2 has a suitable rectangular notch l 24 cut'therein receive the coil 22. The core 18 is secured to the trarne 'l2 qhy-tlnee bolts 26 which 'pass through the frame and core, the core being separated Yirom the frame hy suitable washers 28. The core is thus attached to the frame at three points and accurately positioned relative thereto.

A rotor 3G which comprises a magnetic disc having teeth formed on its "periphery is rigidly secured to a rotor shaft 32 which is journalled in suitable hearings 34. The localm ings are formed in bosses on plates 36, to which plates 'oil retaining cups 38 are secured. The rotor shaft 82 has a sleeve 40 rigidly secured thereto, the latter carrying a easing 42 which may contain a viscous liquid and a looseiy mounted iy-wheel or other suitable means for preventing hunting ot the armature and for making-the motor automatically fall into step when launched at a speed above synchronism. This mechanism is more fully disclosed and claimed .in my copending application, Serial No. 364,480, iiled May 20, 1929, Patent No. 1,719,805, granted July 2, 1929. A pinion 44 is also rigidly secured to the shaft 32, this pinion meshing with a gear 46 which is rigid with a pinion 48 and with a shaft 50. 'A gear 52 which is nggidly con neoted toa pinion 54, and both of which are loosely mounted upon an intermediate shaft56, meshes with the pinion 48. A gear 58 and a pinioni 60 are fastened to a second hand shaft 62. the formenme'shing with the pinion 54 and the latter with a gear 64 pinion meshes with a gear 68 'which is ro-v rigidly secured to the shaft 56. A pinion 66 is rigidly secured to the forward end of the shaft 56 `.in front of the frame 10 and this tatable on shaft 62 and is frictionally held against a pinion 72 by a spring 7 3. The pinion 72 is rigidly secured to the minute hand sleeve 70 and is in mesh with a gear 74.

The gear 74 and a pinion 76 are rigidly secured to the forward end of a setting shaft 78 and which journalled in the frames l0 and 12. The pinion 76 meshes witha gear 80 which is rigidly secured to the hour hand sleeve 82. A second hand 84 is secured to the end of the second hand shaft 62, a minute hand 86 is secured to the sleeve 70, and an hour hand 88 is secured to the sleeve 82.

The hands 84, 86 and 88 register with a suitable dial 90 which is suitably supported either from the frame 10 or from the-casing in which the clockl mechanism is mounted.l This dial has a suitable aperture 92A through which'a segmental disc 94 may be observed, the disc being secured, at the forward end of the shaft 50. Duringthe operation of the clocktliis disc, which is preferably enameled a color contrasting with that of the ldial of the clock, serves as a flashing indication that the clock is running. The rearward end of the shaft has a suitablethumb-pie'ce 96 .secured thereto, this thumb-piece serving as a means forstarting the clock. The shaft 78 has a suitable knurled thumb-piece 98 secured at its rearward end by which the clock may be set. 1

It will be especially noted, from Figs. 1,2- Y and 4, that the' previously described gearJ train is of extremely simple construction and is so arranged as to be very compact and make possible the installation of this mechanism in a small clock.V The fact that Ythe gear 52 and pinion 54 are freely mounted o n the shaft 56 makes possible the elimina; tion of a shaft'which was formerly considered necessary.

It willjbeobserved that the pole pieces 2O are relatively close to the frame 12 so that the magneticv pull exerted upon the rotory does' n ot tend to warp or cant 'the frames relative to each other and thus any tendency of the various shafts to bind in their bearings is prevented. Furthermore, the resultant of the magnetic forces vacting upon the-rotor is speed. As the rotor slows down to synchro-K nous speed, duetwthe frictional load im- \for driving the hour and minute hands from posed by the gear train, it will fall in vste and continue rotation atk synchronous spee The rotor thus drives the hour hand of the clock through the following geartraiii z' pinion 44, gear 46, pinion 48, gear 52,' pinion 54, gear 58, shaft 62, pinion 60, gear 64,shaft 56, pinion 66, gear 68, pinionv 7 2, gear 7 4, pinion 76, and gear 80. The minute hand is of course rotatable with the gear 72 and the second hand rotated by the 'shaft 62.` The shaft 50 will'rotate 'at approximately one revolution per second and the rotation of the disc 94 may readily be observed through the opening 92 in the dial to show that thel clock is operating. 4

In setting the hands of the clock the thumbpiece 98 is rotated in the proper direct'ion'and through the gear 74 and pinion- 72 the pinion 76 and the gear 80 will rotate the hands. The bearingsk3'4 and the ends of the shaft 32 are the only parts ofthe clockf'whi'ch arel subject to substantial wear and since the load on these bearings is appreciably lessened,.$due

to the fact that the resultant of the magnetic forces acts upwardly, and since the bearings are continuously supplied with lubricant from the cups 38, the clockiwill run for a very long period' of time'without any attention. i

The invention i's/capable/f of 'wide variation within equivalent limits and I contemplate such variation as mayl be desirable'or useful in the particular 'adaptation of the invention shown, or in its adaptation to other devices. I do notrestrict myself in anyunessential particulars', but what I claim and desire to secure by Letters 'Patent is':

1. An electric motor driven clock, com prising a shaft geared to said motorandhav'- ing a pinion secured thereto, a second hand shaft, an intermediate shaft, a rigidly connected gear and 'pinion driven by said first'- namedpinion and mounted for free rotation on said intermediate shaft, anda train of gearingdriven fromrsaidgear and pinion and through said second hand shaft and saidn intermediate shaft.-

2. In a motor driven clockahaving indicati inghands and having a gear train in which the drive is from the high speed gears to the low speed gears, `a moton pinion; a gear, a Spui-pinion and shaft rotatable as a unit and thev gear thereof meshing with said vmotor pinion, an' intermediate shaft, a gear and a pinion rotatably mounted4 on said intermediate shaft, the gear thereof meshing with said spur pinion,- a second hand shaft, af pinion and gear rigidly mounted on saidsecond hand shaft.. saidvlast-named gear meshing with said pinion rotatablymounted on said said intermediate shaft and meshing with the pinion on said second hand shaftnand mean/s saidintermediate shaft. d

lintermediate shaft, a gear rigidlysecured to' j l 3. In a speed reduction gearing for motor` driven clocks driving from the high speed end of the train, a pinion (48) rotated by the clock motor, an intermediate shaft, a gear and pinion fixed relative to each other but rotatably mounted on said intermediate shaft, a second shaft, a gear and a pinion rigidly mounted on said shaft,said last-named gear meshing with the said pinion which is rotatable on said intermediate shaft, a gear fixed to said intermediate shaft and meshing with the pinion on said second shaft, and means for driving the clock hands from said intermediate shaft.

4. In a motor driven clock having an indicating hand driving gear train in which the drive is from the high speed gears to the low speed gears, a pinion (44) on. the motor shaft, a gear (46), pinion (48), and shaft (50) rotatable as a unit and the gear (46).( meshing with said pinion (44), an intermediate shaft (56), a gear (52) and a pinion (54) rotatably mounted on said intermediate shaft, the gear (52) meshing with said pinion (48), a second hand shaft (62), a pinion and gear (58) rigidly mounted on said second hand shaft, said gear (58) meshing with said pinion (54), a gear (64) rigidly se- .Cured to said intermediate shaft and meshing with saidpinion (60), a pinion (66) rigidly secured to said intermediate shaft, and gearing meshing with said pinon (66) for drivingthe indicating hands.

5. In an electric motor driven clock having a gear train, a pair of frames, one of said frames having a notch cut therein, an inverted U-shaped core secured to said notched.

frame and lying between the two frames, a. winding about said core, said winding lying partially within the notch in said frame, a motor armature rotatably mounted in said frame, and pole pieces formed on said core at the lower end thereof for cooperation with' said armature.l

6. In an electric motor driven clock, a frame comprising a pair of spaced rigidly joined plates, a gear train mounted 011 said frame, a rotor, a shaft bearing said rotor, carried by said plates and geared `to said train, a laminated core secured adjacent one of said lates on its inner side, and a coil wound a out a portion of said core and extending beyond the outer surface of one of said lates.

7. an electric motor driven clock, a frame comprising a pair ofspaced rigidly joined plates, one of said plates having a recess formed therein, a motor armature', a gear train mounted on said frame and driven pole pieces magnetically connected to said f core and cooperable with said rotor.

In witness whereof, I hereunto subscribe my name this 17th day of June, 1929.

' LAURENS HAMMOND.

by said armature, and a core for said armature rigidly secured to said recessed plate and j forming a reinforcing bridge across said recess..

8. In an electric motor driven clock having a gear train, a pair of frame plates for 

